Enhanced Oil Recovery

Enhanced Oil Recovery

What Is EOR?

Enhanced oil recovery (EOR) is the process of artificially stimulating a reservoir to recover more oil after secondary recovery techniques have become unable to sustain desired production volumes. Additionally, EOR is usually employed when the oil left in the reservoir is trapped in hard-to-reach (low-permeability) sections with poor oil-water contact or irregular fault lines.
The major enhanced oil recovery processes and operations include chemical injection, steam injection, and gas injection. These methods typically require non-standard enhanced oil recovery technology.

1. Gas Injection

Gas injection as an EOR method uses nitrogen gas (N₂) or Carbon dioxide (CO₂) for the miscible displacement of crude in unconventional reservoirs our mature wells. The principle for recovery is that when the gas dissolves in the oil, it reduces its viscosity, improving mobility. According to the US Department of Energy, gas injection techniques account for nearly 60% of EOR production in the United States.

2. Steam Injection

Steam injection enhanced oil recovery (also called thermal recovery or steam flooding) refers to the injection of water vapor at high pressure and temperature into a well to mop up stranded oil from the reservoir following a decline in the formation pressure.

3. Chemical Injection

In chemical injection, long-chain polymers are injected into a well via a chemical injection skid to free up oil and gas molecules from remote sections of the reservoir. Chemical injection can be done alongside waterflooding. This effectively improves the recovery factor by increasing the efficacy of the surfactants for improved mobility of hydrocarbons.